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From: Anders Blomdell <anders.blomdell@domain.hid>
To: xenomai@xenomai.org
Subject: [Xenomai-core] [PATCH] Slow is faster arch/ppc/syslib/open_pic.c
Date: Tue, 07 Feb 2006 17:04:51 +0100	[thread overview]
Message-ID: <43E8C523.2030107@domain.hid> (raw)
In-Reply-To: <43E73441.9090702@domain.hid>

When trying to run Xenomai on PowerPC with OpenPIC, I have (finally) found that 
interrupt latency is much improved with the following patch:



--- arch/ppc/syslib/open_pic.c~ 2006-01-08 03:15:24.000000000 +0100
+++ arch/ppc/syslib/open_pic.c  2006-02-07 16:56:14.000000000 +0100
@@ -820,7 +820,7 @@
   */
  static void openpic_ack_irq(unsigned int irq_nr)
  {
-#ifdef __SLOW_VERSION__
+#if defined(__SLOW_VERSION__) || defined(CONFIG_IPIPE)
         openpic_disable_irq(irq_nr);
         openpic_eoi();
  #else
@@ -831,7 +831,7 @@

  static void openpic_end_irq(unsigned int irq_nr)
  {
-#ifdef __SLOW_VERSION__
+#if defined(__SLOW_VERSION__) || defined(CONFIG_IPIPE)
         if (!(irq_desc[irq_nr].status & (IRQ_DISABLED|IRQ_INPROGRESS))
             && irq_desc[irq_nr].action)
                 openpic_enable_irq(irq_nr);



The reason for this, is that the fast version doesn't call openpic_eoi until the 
interrupt is ended, which means that all RT-interrupts are delayed by a pending 
Linux interrupt.

-- 

Regards

Anders Blomdell


  parent reply	other threads:[~2006-02-07 16:04 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-31 18:53 [Xenomai-core] [PATCH] Shared irqs v.6 Dmitry Adamushko
2006-01-31 19:09 ` Jan Kiszka
2006-01-31 19:50   ` Dmitry Adamushko
2006-01-31 20:14     ` Jan Kiszka
2006-02-01  8:32       ` Jeroen Van den Keybus
2006-02-01  8:46         ` Jan Kiszka
2006-01-31 19:40 ` Jan Kiszka
2006-02-01 13:59 ` [Xenomai-core] Are XN_ISR_CHAINED and XN_ISR_ENABLE mutually exclusive? Anders Blomdell
2006-02-01 14:52   ` Jan Kiszka
2006-02-01 15:00     ` Anders Blomdell
2006-02-01 15:26       ` Anders Blomdell
2006-02-06 11:34   ` [Xenomai-core] [BUG] problems with adeos-ipipe-2.6.14-ppc-1.2-00.patch Anders Blomdell
2006-02-06 18:44     ` Philippe Gerum
2006-02-07 16:04     ` Anders Blomdell [this message]
2006-02-07 16:16       ` [Xenomai-core] [PATCH] Slow is faster arch/ppc/syslib/open_pic.c Philippe Gerum
2006-02-08  9:40         ` Philippe Gerum
2006-02-08 17:57           ` Philippe Gerum

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